Method and apparatus for control of enhanced dedicated channel transmissions

ABSTRACT

A method and apparatus for controlling enhanced dedicated channel (E-DCH) transmissions are disclosed. A plurality of primary absolute grants are received, wherein the plurality of primary absolute grants are associated with a TTI. At least one relative grant is received for E-DCH transmission, wherein the at least one relative grant is associated with the TTI. At least one serving grant for E-DCH transmission is determined. A H-ARQ process is identified for use for the TTI. It is determined whether the identified H-ARQ process is available for scheduled data and whether scheduled data is allowed to be transmitted in the TTI based at least on the identified H-ARQ process. On a condition that the identified H-ARQ process is available for scheduled data and scheduled data is allowed to be transmitted in the TTI, scheduled data is allocated for transmission in the TTI.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/523,306 filed Jun. 14, 2012, which is a continuation of U.S. patentapplication Ser. No. 11/444,751 filed May 31, 2006 which issued Jun. 19,2012 as U.S. Pat. No. 8,204,007, which claims the benefit of U.S.provisional application No. 60/704,273 filed Aug. 1, 2005, the contentsof which are incorporated by reference herein as if fully set forth.

FIELD OF INVENTION

The present invention is related to wireless communication systems. Moreparticularly, the present invention is related to a method and apparatusfor controlling enhanced dedicated channel (E-DCH) transmissions.

BACKGROUND

Methods for improving uplink (UL) coverage, throughput and transmissionlatency are currently being investigated in the third generationpartnership project (3GPP). In order to achieve these goals with respectto an E-DCH, the control of UL resources, (i.e., physical channels), hasbeen moved from the radio network controller (RNC) to the Node-B.

In order to reduce complexity and power consumption, execution ofwireless transmit/receive unit (WTRU) side enhanced uplink medium accesscontrol (MAC-e/es) functions, such as E-DCH transport format combination(E-TFC) selection and multiplexing, remaining transmit powercalculation, and processing of absolute grants (AGs) and relative grants(RGs), needs to be properly controlled and coordinated.

SUMMARY

The present invention is related to a method and apparatus forcontrolling E-DCH transmissions. A MAC-e/es entity of the WTRU receivesa scheduling grant and processes the scheduling grant to calculate aserving grant. The MAC-e/es entity determines whether both a hybridautomatic repeat request (H-ARQ) process for scheduled data and thescheduled data are available. If an H-ARQ process for scheduled data andthe scheduled data are both available, the MAC-e/es entity determineswhether a serving grant exists. The MAC-e/es entity then calculates aremaining power based on the maximum allowed power and restricts anE-TFC based on the remaining power. The MAC-e/es entity selects an E-TFCusing the serving grant and generates a MAC-e protocol data unit (PDU)for transmission. The MAC-e/es entity may process the received scheduledgrant at each transmission time interval (TTI), or may store thereceived scheduled grant in a grant list until there is E-DCH data totransmit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a wireless communication system configuredin accordance with the present invention.

FIG. 2 is a block diagram of a protocol architecture of a WTRU inaccordance with the present invention.

FIG. 3 is a block diagram of a MAC-e/es entity of a WTRU in accordancewith the present invention.

FIG. 4 is a flow diagram of a process for controlling E-DCHtransmissions in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

When referred to hereafter, the terminology “WTRU” includes but is notlimited to a user equipment (UE), a mobile station, a fixed or mobilesubscriber unit, a pager, or any other type of device capable ofoperating in a wireless environment. When referred to hereafter, theterminology “Node-B” includes but is not limited to a base station, asite controller, an access point (AP) or any other type of interfacingdevice in a wireless environment.

The present invention is applicable to any wireless communicationsystems including, but not limited to, universal mobiletelecommunication systems (UMTS) frequency division duplex (FDD), UMTStime division duplex (TDD) and time division synchronous code divisionmultiple access (TD-SCDMA) systems.

The features of the present invention may be incorporated into anintegrated circuit (IC) or be configured in a circuit comprising amultitude of interconnecting components.

FIG. 1 is a block diagram of a wireless communication system 100configured in accordance with the present invention. The system 100comprises a WTRU 102, a Node-B 104 and an RNC 106. The RNC 106 controlsoverall E-DCH operation by configuring E-DCH parameters for the Node-B104 and the WTRU 102, such as initial transmit power level, maximumallowed transmit power or available channel resources per Node-B.Between the WTRU 102 and the Node-B 104, an E-DCH 108, an E-DCHdedicated physical control channel (E-DPCCH), an absolute grant channel(E-AGCH) 112, a relative grant channel (E-RGCH) 114 and an H-ARQinformation channel (E-HICH) 116 are established for supporting E-DCHoperations.

For E-DCH transmissions, the WTRU 102 sends scheduling information,(also known as a rate request), to the Node-B 104 via the E-DPCCH 110.The Node-B 104 sends a scheduling grant to the WTRU 102 via the E-AGCH112 or the E-RGCH 114. After E-DCH radio resources are allocated for theWTRU 102, the WTRU 102 transmits UL data via the E-DCH 108. In responseto the E-DCH transmissions, the Node-B 104 sends an acknowledgement(ACK) or non-acknowledgement (NACK) message for H-ARQ operation via theE-HICH 116. The Node-B 104 may also respond with rate grants to the WTRU102 in response to E-DCH data transmissions.

FIG. 2 is a block diagram of a protocol architecture of the WTRU 102 inaccordance with the present invention. The protocol architecture of theWTRU 102 includes higher layers 202, a radio link control (RLC) layer204, a MAC layer 206 and a physical layer 208. The MAC layer 206includes a dedicated channel medium access control (MAC-d) entity 210and a MAC-e/es entity 212. The MAC-e/es entity 212 handles all functionsrelated to the transmission and reception of an E-DCH including, but notlimited to, H-ARQ transmissions and retransmissions, priority of data,MAC-d and MAC-es multiplexing, and E-TFC selection. The RLC layer 204 isprovided for in-sequence delivery of data. A re-ordering function isprovided in the RLC layer 204 to organize the received data blocksaccording to the sequence.

FIG. 3 is a block diagram of the MAC-e/es entity 212 in accordance withthe present invention. The MAC-e/es entity 212 includes an E-TFCselection entity 302, a multiplexing and transmission sequence number(TSN) setting entity 304, an H-ARQ entity 306, a serving grantprocessing entity 308 and a memory 310. The serving grant processingentity 308 receives an AG 312 and a RG(s) 314 from the physical layer208 and processes the AG 312 and the RG(s) 314 to generate a servinggrant or stores them in the memory 310. There may be one or more RGs314. The E-TFC selection entity 302 selects an E-TFC based on theserving grant and performs an arbitration among different data flowsmapped on the E-DCH.

The multiplexing and TSN setting entity 304 concatenates multiple MAC-dPDUs into MAC-es PDUs, and multiplexes one or multiple MAC-es PDUs intoa single MAC-e PDU to be transmitted in the next TTI as instructed bythe E-TFC selection entity 302. The multiplexing and TSN setting entity304 also manages and sets a TSN per logical channel for each MAC-es PDU.

The H-ARQ entity 306 controls a plurality of H-ARQ processes for storingMAC-e PDUs and retransmitting the MAC-e PDUs when a transmission failureis signaled via the E-HICH. An active H-ARQ process is used fortransmission of scheduled data, while a non-active H-ARQ process is notused for transmission of scheduled data. At a given TTI, the H-ARQentity 306 identifies an H-ARQ process for which a transmission shouldtake place. At the time of a new transmission, the H-ARQ entity 306provides an H-ARQ profile for all new transmissions and retransmissionsof a MAC-e PDU. The H-ARQ profile includes information on the maximumnumber of transmissions and a power offset with which to configure thephysical layer.

The execution of the E-TFC selection by the E-TFC entity 302 depends onthe availability of data mapped to the E-DCH with a grant (including anoccurrence of a scheduling information rate request trigger) and theavailability of an H-ARQ process. An H-ARQ process should be availablebefore E-TFC selection is performed by the E-TFC selection entity 302.The H-ARQ entity 306 identifies to the E-TFC selection entity 302 theavailability of H-ARQ processes. H-ARQ processes may be available uponinitial configuration, ACK reception, or exceeding the maximum number ofretransmissions for any H-ARQ processes.

FIG. 4 is a flow diagram of a process 400 for controlling E-DCHtransmissions in accordance with the present invention. A physical layerreceives a scheduling grant via an E-AGCH 112 and E-RGCHs 114 (step402). After decoding of E-AGCH and E-RGCH, an AG 312 and RG(s) 314 aresent to the serving grant processing entity 308 in the MAC-e/es entity212. The serving grant processing entity 308 processes the AG 312 andRG(s) 314 to determine a serving grant. The scheduling grant may be anAG 312 from a serving E-DCH cell or an RG(s) 314 from either all cellsin a serving E-DCH radio link set (RLS) or a non-serving radio link(RL). The scheduling grant is applied to a specific transmission timeinterval (TTI). This association is implicit based on the timing of theAG 312 and the RG(s) 314.

Upon reception of the scheduling grant, the serving grant processingentity 308 has two options when there is no data to transmit in the TTIassociated to the scheduling grant. The serving grant processing entity308 may process the received scheduling grant to determine a currentserving grant each TTI (step 404). Alternatively, the serving grantprocessing entity 308 may store the received scheduling grant in amemory 310, (i.e., a grant list), and process the stored schedulinggrants when there are E-DCH data to transmit.

The E-TFC selection entity 302 determines whether any H-ARQ processesfor scheduled data, (i.e., an active H-ARQ process) and scheduled dataare both available (step 406). If an H-ARQ process for scheduled dataand scheduled data are both available, the process 400 proceeds to step410 to determine whether a serving grant exists. Alternatively, if boththe H-ARQ process for scheduled data and the scheduled data are bothavailable, and if the second option is implemented, (i.e., the receivedscheduling grant is stored in the memory 310), the serving grantprocessing entity 308 processes the scheduling grant stored in thememory 310 to determine a serving grant at step 408 before proceeding tothe step 410.

A serving grant indicates a maximum E-DPDCH to dedicated physicalcontrol channel (DPCCH) power ratio that the WTRU is allowed to allocatefor the upcoming transmission for scheduled data. The serving grant isupdated based on the AG and the RG.

In processing the scheduling grant stored in the grant list, the servinggrant processing entity 308 may process the last N AGs among the storedscheduling grants to generate the serving grant. The value of N islarger than one.

Alternatively, the serving grant processing entity 308 may maintain onlythe most recent primary AG and subsequent RGs, including the latestsecondary AG in the grant list. A primary AG is an AG received with aprimary radio network temporary ID (RNTI) and a secondary AG is an AGreceived with a secondary RNTI. When a new primary AG is receivedprevious AG and RGs except for the last secondary AG are removed fromthe grant list when the next transmission requiring a scheduling grantoccurs. This reduces significant processing overhead followingtransmission idle periods.

In addition, whenever a serving cell change occurs, the serving grantprocessing entity 308 discards all stored AGs and RGs in the grant list.This operation is equivalent to setting an AG to zero and discarding allRGs.

At step 410 if it is determined that there is no serving grant, (i.e., acurrent serving grant is zero), the E-TFC selection entity 302 limits anE-TFC to a minimum set of E-TFCs (step 412) and calculates a remainingpower based on the minimum set of E-TFCs (step 414). If it is determinedthat there is a serving grant at step 410, the E-TFC selection entity302 calculates a remaining power based on a maximum allowed power (step414).

After the remaining power is calculated, the E-TFC selection entity 302restricts E-TFCs for this TTI based on the remaining power (step 416).The E-TFC selection entity 302 then selects an E-TFC and themultiplexing and TSN setting entity 304 generates a MAC-e PDU bymultiplexing MAC-d flows and MAC-es PDUs (step 418). A happy bit whichindicates whether the WTRU is satisfied with a current scheduling grantis then set for transmission in this TTI (step 420) and the MAC-e/esentity waits for the next TTI (step 422).

If it is determined at step 406 that either an H-ARQ process forscheduled data, (i.e., an active H-ARQ process), is not available orscheduled data is not available, the E-TFC selection entity 302 thendetermines whether an H-ARQ process for non-scheduled data and thenon-scheduled data are both available (step 424). If an H-ARQ processfor non-scheduled data and the non-scheduled data are both available,the E-TFC selection entity 302 further determines whether there is anynon-scheduled grant (step 426). The non-scheduled grant is set by an RNCin terms of maximum number of non-scheduled bits that can be included ina MAC-e PDU. The WTRU is allowed to transmit non-scheduled transmissionsup to the sum of the non-scheduled grant if multiplexed in the same TTI.If there is a non-scheduled grant, the process proceeds to step 414 tocalculate a remaining power and subsequent MAC-e functions, (i.e., steps416-422), are performed as described hereinbefore.

If it is determined at step 426 that there is no non-scheduled grant, itis determined whether there is any H-ARQ processes available (step 428).If there is an available H-ARQ process, it is determined if schedulinginformation needs to be reported, (i.e., whether a triggering eventoccurs) (step 430).

Reporting of scheduling information is triggered by a plurality ofdifferent events, which are configurable. Generation of schedulinginformation is well known in the art and is not within the scope of thepresent invention. If it is determined at step 430 that there isscheduling information that needs to be transmitted, schedulinginformation bits are generated (step 432) and the process proceeds tostep 414 to calculate a remaining power. Subsequent MAC-e functions,(i.e., steps 416-422), are then performed as described hereinbefore. Ifthere is no scheduling information to be transmitted, no newtransmission occurs in this TTI and the MAC-e entity waits for the nextTTI (step 422).

If it is determined at step 428 that there is no available H-ARQprocess, (which means that the transmission in this TTI is aretransmission), a happy bit is set for the transmission in this TTI toindicate whether the WTRU is satisfied with the scheduling grant (step434) and the MAC-e entity waits for the next TTI (step 422).

Although the features and elements of the present invention aredescribed in the preferred embodiments in particular combinations, eachfeature or element can be used alone without the other features andelements of the preferred embodiments or in various combinations with orwithout other features and elements of the present invention.

What is claimed is:
 1. A method, implemented by a wirelesstransmit/receive unit (WTRU), the method comprising: receiving aplurality of primary absolute grants for enhanced dedicated channel(E-DCH) transmission, wherein the plurality of primary absolute grantsare associated with a transmission time interval (TTI); receiving atleast one relative grant for E-DCH transmission, wherein the at leastone relative grant is associated with the TTI; determining at least oneserving grant for E-DCH transmission based on at least one primaryabsolute grant of the plurality of primary absolute grants and the atleast one relative grant; identifying a hybrid automatic repeat request(H-ARQ) process for use for the TTI; determining whether the identifiedH-ARQ process is available for scheduled data, wherein only an activeH-ARQ process is used for transmission of scheduled data and anon-active H-ARQ process is not used for transmission of scheduled data;determining whether scheduled data is allowed to be transmitted in theTTI based at least on the identified H-ARQ process; on a condition thatthe identified H-ARQ process is available for scheduled data andscheduled data is allowed to be transmitted in the TTI, allocatingscheduled data for transmission in the TTI; calculating a remainingpower available for the TTI based on a maximum allowed power for theWTRU; performing E-DCH transport format combination (E-TFC) restrictionbased on the remaining power; selecting an E-TFC from a set of E-TFCsremaining after E-TFC restriction, wherein the E-TFC selection is basedat least on the at least one serving grant; and transmitting theallocated data in accordance with the identified H-ARQ process.
 2. Themethod of claim 1 wherein the allocating scheduled data for transmissionfurther comprises: concatenating multiple medium access control (MAC)for dedicated channel (MAC-d) protocol data units (PDUs) into at leastone MAC-es PDU; and multiplexing the at least one MAC-es PDU into onemedium access control for enhanced uplink (MAC-e) PDU.
 3. The method ofclaim 1 wherein a primary absolute grant is received over an E-DCHabsolute grant channel (E-AGCH).
 4. The method of claim 1 wherein arelative grant is received over an E-DCH relative grant channel(E-RGCH).
 5. The method of claim 1 further comprising receiving feedbackinformation regarding the transmitted data, wherein the feedbackinformation is received over an E-DCH H-ARQ indicator channel (E-HICH).6. A wireless transmit/receive unit (WTRU) comprising: circuitryconfigured to receive a plurality of primary absolute grants forenhanced dedicated channel (E-DCH) transmission, wherein the pluralityof primary absolute grants are associated with a transmission timeinterval (TTI); circuitry configured to receive at least one relativegrant for E-DCH transmission, wherein the at least one relative grant isassociated with the TTI; circuitry configured to determine at least oneserving grant for E-DCH transmission based on at least one primaryabsolute grant of the plurality of primary absolute grants and the atleast one relative grant; circuitry configured to identify a hybridautomatic repeat request (H-ARQ) process for use for the TTI; circuitryconfigured to determine whether the identified H-ARQ process isavailable for scheduled data, wherein only an active H-ARQ process isused for transmission of scheduled data and a non-active H-ARQ processis not used for transmission of scheduled data; circuitry configured todetermine whether scheduled data is allowed to be transmitted in the TTIbased at least on the identified H-ARQ process; on a condition that theidentified H-ARQ process is available for scheduled data and scheduleddata is allowed to be transmitted in the TTI, circuitry configured toallocate scheduled data for transmission in the TTI; circuitryconfigured to calculate a remaining power available for the TTI based ona maximum allowed power for the WTRU; circuitry configured to performE-DCH transport format combination (E-TFC) restriction based on theremaining power; circuitry configured to select an E-TFC from a set ofE-TFCs remaining after E-TFC restriction, wherein the E-TFC selection isbased at least on the at least one serving grant; and circuitryconfigured to transmit the allocated data in accordance with theidentified H-ARQ process.
 7. The WTRU of claim 6 wherein the circuitryconfigured to allocate scheduled data for transmission furthercomprises: circuitry configured to concatenate multiple medium accesscontrol (MAC) for dedicated channel (MAC-d) protocol data units (PDUs)into at least one MAC-es PDU; and circuitry configured to multiplex theat least one MAC-es PDU into one medium access control for enhanceduplink (MAC-e) PDU.
 8. The WTRU of claim 6 wherein the WTRU isconfigured to receive a primary absolute grant over an E-DCH absolutegrant channel (E-AGCH).
 9. The WTRU of claim 6 wherein the WTRU isconfigured to receive a relative grant over an E-DCH relative grantchannel (E-RGCH).
 10. The WTRU of claim 6 further comprising circuitryconfigured to receive feedback information regarding the transmitteddata, wherein the WTRU is configured to receive the feedback informationover an E-DCH H-ARQ indicator channel (E-HICH).